The present invention relates to a receiving gripper for a rapier loom, comprising a hook having on its inside a clamping surface extending obliquely to the longitudinal direction of the gripper, and a clamping element having a clamping surface associated with the hook""s clamping surface, said clamping element being displaceable substantially in the longitudinal direction of the gripper against a spring from a clamped position into an open position and being supported and guided by a guide on the side which is opposite said clamping surface.
As regards a receiving gripper of the initially cited kind and illustratively described in British patent 2,106,550A, the clamping element will be guided along its direction of displacement. This design entails a comparatively large excursion for the element to reach its open position in order to release a filling.
It is known from the European patent document 0,123,005B to design the guide as an oblique, plane path running opposite the hook""s clamping surface. As a result, the clamping element moving along this path will release a filling after a comparatively short opening displacement because an oblique, transverse displacement is carried out in addition to the longitudinal displacement of the clamping element.
When using a receiving gripper, the filling must be reliably kept in place between the clamping surfaces of the hook and the clamping element. The clamping forces must be large enough to preclude accelerations or decelerations from moving the clamping element out of its clamping position, or to be affected by external vibrations applied to the gripper. These forces are applied by a spring loading the clamping element. As regards the design of the European patent document 0,123,005, a comparatively stiff spring is required because the clamping element in its clamping position rests not only against the hook""s clamping surface but also against the guide. The spring stiffness affects the loads of the clamping surfaces of the guide means and the other drive elements and connectors between a drive lever and the clamping element. High spring forces entail commensurately high stresses and wear. Accordingly the advantage of rapid release of a filling is a tradeoff against the drawback of higher wear in the design of the European patent document 0,123,005B1.
The objective of the invention is to create a receiving gripper of the initially cited kind which shall open rapidly while at the same time not be subjected to too high wear.
The invention solves this problem by guiding the clamping element between the open and clamped positions, using the guide, along a curved guide path which, in the zone before the clamping position, is directed toward the hook""s clamping surface and which in the zone of the clamping position, changes over into a section substantially extending in the longitudinal direction of the gripper.
The curved guide path of the guide of the invention attains adequately high clamping forces using a comparatively compliant spring because the clamping element is supported practically solely at the clamping surfaces against the spring force. Nevertheless the curved guidance path allows superposing a relatively large transverse displacement on the longitudinal motion of the clamping element and as a result makes it possible to open the gripper comparatively rapidly.